First-person perspectives on the world of work
Photo: Rafael Duarte/ ILO

The Future of Work Podcast

Episode 58
Heat stress

Heat: a silent killer at work

5 June 2024

The rising temperatures associated with climate change mean more people are experiencing heat stress at work. A recent ILO report, Ensuring safety and health at work in a changing climate estimates that nearly 19,000 workers die annually because of excessive heat, and more than 70 per cent of the global workforce are likely to be exposed to excessive heat at some point during their work.

Manal Azzi, ILO Occupational Safety and Health Team Lead, and Halshka Graczyk, ILO Occupational Safety & Health Technical Specialist, join the Future of Work podcast to discuss what is being done to make workplaces safer and protect workers from the effects of heat stress.



Hello, and welcome to another edition of The Future of Work podcast.

I'm Sandra Kuchen.

The rising temperatures we are seeing with climate change means

more of us are at risk of experiencing heat stress at work.

A recent report from the International Labour Organization

estimates that more than 2.4 billion workers--

and we're talking over 70% of the global workforce,

are likely to be exposed to excessive heat at some point during their work.

So, what's the impact of heat stress on our health?

And, what can be done to make our workplaces

safer and protect workers from heat stress?

Joining the podcast to discuss this with us are Manal Azzi,

the ILO's Occupational Safety and Health Team Lead,

and Halshka Graczyk, an Occupational Safety

and Health Technical Specialist also from the ILO.

Welcome, Manal and Halshka.

Thank you, Sandra.

To get the conversation started,

I'd like us to listen to two people from Mexico.

A farm worker, Alejo, he works in a greenhouse,

as well as Eduardo, a farm employer.

The farms they work at are part of an ILO Vision Zero Fund project

which is measuring heat stress among agricultural workers.

The purpose of the project is to analyze

the link between climate change, rising temperatures,

and safety and health at work.

I thought we could listen to what they have to say

about the impact of heat in their workplaces.

[Spanish language]

I felt a little overwhelmed yesterday because I couldn't stop working.

Then, all of a sudden, it was like my body couldn't take it anymore.

I started feeling palpitations.

That was when I thought, "This is it, I did my best."

I went to drink some water, and then I started to feel better.

When you start feeling sick, like you're getting heatstroke,

you feel like your feet start losing their strength.

Climate change is an important issue for us.

For example, when we look at last year, it led to hotter temperatures.

The rainy season is when it gets really hot around here,

and the rains arrive nearly a month early.

Temperatures were supposed to drop during that month,

but they actually went up a bit.

As a result, you get more pests,

and the farm workers' performance drops

because they get more physically exhausted than expected.

Manal, when you hear these experiences from Mexico,

what's your immediate reaction?

How big a problem is heat stress for people in the workplace?

What are we looking at here?

Thanks, Sandra.

It's actually a reflection of a very sad truth that we're living.

It's very good to hear live examples because we get told,

often, "What does the world of work,

what does health have to do with climate change?"

And this is your example,

a concrete example of what's happening on the ground,

in the field, for people exposed to excessive heat.

How it's affecting their health.

We know, from the numbers,

that we're looking at more than 22 million people living

with occupational injuries related to this kind of exposure,

and that's leading to more than 19,000 deaths annually

because of excessive heat,

not to mention the 26 million people living with chronic kidney disease,

that we are very clear it is now attributable

to the exposure, to excessive heat at work.

So the scope of the problem

and the prevalence of the issue is quite clear.

That's why hearing our field workers

in Mexico is really important to shed light on that.

I think something that was said

that's really important is about the increase in pests.

That's a really related area where,

because of the increase in changing pests and changing seasons,

and changing rainfalls, and patterns of crops,

we're needing to use more pesticides.

We're using a lot more agrochemicals.

That's adding another health hazard for workers,

at least in the agricultural world.

The interrelation between excessive heat and the other exposures

that are linked to excessive heat or that create changes in working

patterns that also create more hazards that need to be dealt

with makes this a cumulative effect that workers are facing today.


There's a real knock-on effect of where this could lead.

Absolutely, yes.

Clearly, this is a major issue.

Halshka, I'm curious, what qualifies as excessive heat?

Is it a certain temperature, are we talking about?

But I guess humidity also plays a factor, and then,

what impact does it have on a worker's health?

Yes, Sandra, that's a very interesting question

because we know that not all heat is hazardous.

Heat becomes hazardous once it overwhelms

the body's capacity to maintain its safe body temperature.

What we know is that it's not just heat.

It's exactly what you said.

We have heat, we have humidity, we have direct UV radiation.

We have to really consider the work task.

There's a real difference in the bodily store of heat,

if we're talking about a worker that's sitting

at a desk working in the heat,

or a worker that's carrying very heavy loads and using

big materials and having to really exert themselves, right?

We're also talking about what Manal mentioned

in the pesticide spraying, we're talking about really heavy PPE,

workers that are wearing PPE that's not breathable.

"PPE" being personal protective equipment.

Thinking about firefighters, thinking about pesticide sprayers,

thinking about workers in heavy industries that have to be wearing

clothing that is not breathable and also that is,

therefore, increasing their heat load in their body.

So there's many different issues that we need to be thinking about.

Now, these rapid rises in body temperatures can really lead

to a cascade of health-related illnesses,

and this is where it becomes very worrying

for the safety and health of workers.

We heard, in the recording, starting with palpitations,

things like weaknesses, dizziness, loss of feeling sometimes in the limbs.

This can really quickly escalate to things like heat exhaustion,

heat stroke, which could become lethal if not immediately treated.

This is the reason sometimes we call heat the silent killer,

because of its rapid onset, the rapid rise in body temperatures,

and that cascade that I just mentioned.

Now, we also have to think about the chronic health impacts,

the kidney diseases that Manal mentioned.

26 million workers, at least,

suffering from those chronic kidney diseases.

Now, there's also a direct correlation

between the heat and cognitive abilities.

The risk for accidents, injuries, falls, slips,

that loss of concentration that's related to that increased heat,

and how that affects the worker's safety and health.

There's also mental health impacts, right?

There's irritation, anxiety, loss of focus,

loss of the ability to sleep well, and, therefore, the next day,

going back to work, in the heat,

losing focus and having the risk of increased accidents.

There's really this multitude of health impacts that we're seeing.

There's a multitude of health risks,

and we're needing to really develop strategies that look

at all of those in combination because, without it,

we're only seeing a small piece of the health impact puzzle.

Where is this happening?

We've seen that agricultural work is one of the sectors,

but where else are workers

disproportionately affected by excessive heat?

-Manal? -Sure.

Over 870 million people work in agriculture,

so that's already a huge number of people

exposed to outdoor excessive heat.

We see it in construction,

we see it in a number of sectors where people are working outside,

but the problem that sometimes we forget

is that there is a lot of excessive

heat happening indoors as well that's poorly regulated.

In indoor places where there's poor ventilation,

where people are doing repetitive movements,

or in addition to other ergonomic factors that could be at play

even exacerbate the effects of excessive heat.

Really, outdoor workers across a number of sectors,

and indoor workers in manufacturing

and other kinds of work that are affected

by poor ventilation and excessive heat

and humidity and everything that comes with it.

Right, so the numbers that you've given us are huge.

The impacts are really significant, so what can we do about it?

What can someone listening to this podcast--

if they're experiencing excessive heat

and they're starting to feel unwell, what can they do?

And, more importantly,

what can their employer be doing to help prevent heat stress?

-Yes, Sandra. Well, this is where we have good news.

We know that there are cost-effective, practical solutions

at the workplace to help regulate this issue.

One of the first things we can do

is having recognized work-rest ratios

where we have the ability to rest in shaded, cool areas.

Now, this comes with the ability to rest,

so having the employer that recognizes that these things

are needed to help worker safety and health,

but also to help with productivity issues.

We know that we also need

to have a supply of clean drinking water, right?

Hydration is critical.

Having the ability to stop, take those water breaks.

With this comes a very important element

of having sanitary facilities, right?

Imagine a worker in a agricultural field,

and if they are told they should be drinking water,

fine, but also, we need to have those breaks available,

and the sanitary facilities available,

especially for women workers in these kinds of situations.

Okay, then, why don't we broaden out here?

Because this is a collective issue that concerns everybody.

If we look at governments and the social partners,

the employers and the workers, what policies,

what actions can they be putting in place

to protect workers from heat stress?

Exactly, and a lot is happening.

It's important to note that this is not a new issue,

obviously, and a lot of people are saying,

"The sun is not new, the heat is not new."

It's been there, and it has been regulated

through occupational safety and health measures,

but also through public health measures

and through environmental health measures,

but people are now scaling up the changes and improving

and evolving their policies to cover some of these issues.

We've got training programs, technical guidelines,

global strategies to manage these issues that look

at exposure limits that need to be defined,

exposure limits to excessive heat,

the breaks that need to be taken by workers,

and the recognition of some of these diseases

that Halshka mentioned earlier that needs

to be compensated for and recognized

as an occupational disease in some of these lists.

There are many initiatives,

both in collaboration with workers and collective

bargaining sometimes plays a big role to recognize

exposure to excessive heat as an occupational issue

in defining policies and defining solutions for them.

Yes, and I think we also need to think about the idea

of having regular medical surveillance of workers.

A lot of times when we're talking about heat stress,

there's this jump to think about heat waves

and looking at specifically those crisis moments.

However, what we know from the evidence is that heat

can impact workers' health also just during hot days

and not just during periods of heat waves.

Therefore, that idea of regular medical surveillance is really key.

Another issue is the training of workers.

There's not always an immediate understanding

that heat is affecting your body.

That is something critical,

the recognition of when heat stress is starting to impact,

and how workers can understand that and take action.

And have the right to.

They need to be pacing themselves,

they have the right to remove themselves if they feel

that they're in danger without facing retaliation.

You're talking about rights there, and the International Labour Organization

is a standard-setting organization.

To what extent is this built

into the existing international labour standards?

Yes, absolutely.

We already have a number of standards,

Conventions that aim to help regulate

the environment and the ambient temperatures.

We have codes of practice that are somehow outdated,

but still stand relevant today.

That's why, at the ILO, there is a plan, in the next year,

to call together our constituents and discuss,

through a tripartite expert meeting,

the impact of climate change on occupational safety and health.

I think that's going to be a great opportunity.

Halshka will be working heavily on this to actually come up with,

for the first time, global policy guidance and recommendations,

hopefully, in 2025, to guide governments

on their development of their policies

and how to regulate the impact of climate change,

which is, of course, broader than just excessive heat,

but excessive heat, I think, is the crucial part of the puzzle.

Because this problem isn't going to go away anytime soon, is it?

It's set to grow.

It's set to grow.

That's one of the main problems, is that it's just--

it's been happening for years now and a lot of people

just developed their awareness around it just now.

That's why we need to be learning from governments

that have already made a lot of big leaps to manage this,

because they've seen their workers fall

and die for so many different reasons,

and they're losing their workforce and their main asset,

so now they're taking action,

and we're here to help accelerate this action

and actually share experiences between different regions,

because what we're also seeing is that some regions

are very familiar with excessive heat and the impacts of heat

and some are just starting

to face it because of the changing climate and the warming of the planet,

and certain work arrangements that never

were in place before are being more affected.

We're having to keep looking at our regulations

and keep improving our guidance, because understanding human physiology,

understanding how we are acclimatized or not to heat,

how long it takes for maybe migrant workers

from sending, receiving countries.

There are so many issues we need to deal with

when we're trying to prevent the onset of heat stress

and the onset of the very serious health impacts

that this can lead to for our workforce.

It sounds like you have a lot to be getting on with.

You said that there's a report coming out soon with new figures?

Yes, Sandra, very exciting.

In a few weeks, we will be releasing a new report on heat at work,

looking at some of the evidence base, looking at what countries are doing,

and also some of the practical responses

that can be taken at the workplace level.

What we're really hoping that this report brings

is an opening of a dialogue on this discussion

on workplace safety and health, on what can be done,

and how we can move closer to the meeting that Manal mentioned,

the tripartite meeting with our constituents to see

what kind of practical recommendations we can bring to the world of work.


Sounds like you've got a busy schedule there.

Thank you very much, Manal and Halshka, for taking the time to talk to us.

No doubt we will revisit the subject

of workplace heat stress in the future.

For now, that brings us to the end of our podcast.

To our listeners, thank you for joining, and until the next edition

of the ILO's Future of Work podcast, goodbye.